Fastener

Abstract

A fastener has a metallic member and a nonmetallic cap member. The metallic member has a head and a shaft. The shaft has a first end at the head, a distal second end, and an externally threaded portion. The metallic member further has a projection extending from the head opposite the shaft. The cap member is mated to the head opposite the shaft and retained by the projection.

1 . A fastener comprising: 
 a metallic member having: 
 a head;  
 a shaft having: 
 a first end at the head;  
 a distal second end; and  
 an externally threaded portion; and  
 
 projection extending from the head opposite the shaft; and  
   a nonmetallic cap member mated to the head opposite the shaft and retained by the projection.    
     
     
         2 . The fastener of  claim 1  wherein: 
 the shaft further comprises a gripping feature adjacent the second end.    
     
     
         3 . The fastener of  claim 1  wherein: 
 the gripping feature comprises at least one of:    internal facets, internal splines, external facets, and external splines.    
     
     
         4 . The fastener of  claim 1  wherein: 
 the gripping feature comprises a hexagonal-section compartment.    
     
     
         5 . The fastener of  claim 1  wherein: 
 an underside of the head and an underside portion of the cap form a stepped frustoconical surface.    
     
     
         6 . The fastener of  claim 1  wherein: 
 the cap comprises or consists essentially of a ceramic matrix composite.    
     
     
         7 . The fastener of  claim 1  further comprising: 
 an internally threaded nut in threaded engagement with the shaft.    
     
     
         8 . An engine exhaust panel assembly comprising: 
 a panel having a first surface exposed to an exhaust flowpath of the engine;    a support structure supporting the panel; and    a fastener according to  claim 1  securing the panel to the support structure.    
     
     
         9 . The assembly of  claim 8  wherein: 
 the head and cap are flush or sub-flush in a bevel of the panel.    
     
     
         10 . The assembly of  claim 8  wherein: 
 a nut is engaged to the shaft.    
     
     
         11 . A method for manufacturing a fastener comprising: 
 mating a non-metallic cap member to a projection from a head of a metallic member; and    deforming the projection to a deformed configuration retaining the cap member.    
     
     
         12 . The method of  claim 11  wherein: 
 the deforming comprises melting.    
     
     
         13 . The method of  claim 11  further comprising: 
 manufacturing the metallic member, including: 
 cutting an external thread on a shaft opposite the projection; and  
 forming a compartment in an end of the shaft opposite the projection.  
   
     
     
         14 . A fastener comprising: 
 a ceramic matrix composite cap;    a metallic member having a head and a threaded shaft; and    means securing the cap to the head.    
     
     
         15 . The apparatus of  claim 14  further comprising: 
 means for engaging the metallic member.    
     
     
         16 . The apparatus of  claim 15  wherein: 
 the means for engaging the metallic member comprises an internal compartment in a distal end of the shaft.    
     
     
         17 . The apparatus of  claim 14  wherein: 
 an underside of the head and an underside portion of the cap form a stepped frustoconical surface.    
     
     
         18 . A method for assembling an engine exhaust panel assembly comprising: 
 inserting the shaft of a fastener according to  claim 14  through an aperture in a ceramic matrix composite panel and an aperture in a support structure;    engaging the shaft to an internally threaded nut;    engaging the nut with a tool;    engaging an feature of the shaft with said tool or another tool; and    relatively rotating the nut and fastener to tighten the nut to the fastener.    
     
     
         19 . The method of  claim 18  wherein: 
 the tool is a wrench; and    said another tool is a hex-key.